Centrifugal governor



Jan. 11, 1944. DRAPER 2,338,761

CENTRIFUGAL GOVERNOR Filed Feb. 12, 1942 4 Sheets-Sheet l a FIG t;wvsmvk AD HAPE I Jan. 11, 1944" A. D. DRAPER CENTRIFUGAL GOVERNOR FiledFeb. 12, 1942 4 Sheets-Sheet 2 Jan. 11, 1944. DRAPER 2,338,761

' CENTRIFUGAL GOVERNOR Filed Feb. 12, 1942 4 Sheets-Sheet 3 Jan. 11,1944. DRAPER 2,338,761

CENTRIFUGAL GOVERNOR Filed Feb. 12, 1942 4 Sheets-Sheet 4 Patented Jan.11, 1944 Application February 12, 1942, Serial No. 430,697

In Great Britain March 28, 1941v 6 Claims.

This invention relates to centrifugal governors intended moreparticularly for controlling the speed of internal combustion enginesand in which the movement of weights against a spring causes actuationof the throttle or otherwise controls the engine.

In the following description, the word strength is used as meaning theratio of load to tension. .The tension means the degree of stretching.It is desirable to be able to adjust a governor with respect to thestrength of the spring without affecting the tension, because it iscommonly specified that a governor must control the engine at variousspeeds with a maximum variation at each speed between light load andfull load. This requirement can be met by providing an adjustment forvarying the strength of the spring, but such adjustment must not affectthe spring tension, since the tension setting determines the speedvariation between light load and full load. In at least one knownarrangement in which this adjustment can be effected. it is not easy toalter the strength of the spring without afiecting the setting withrespect to the tension. With this invention this defect is avoided.

According to this invention in a governor for the purpose indicated oneend of the efiective part of a coiled spring is carried by a memberadjustably connected to a part which takes the spring reaction and thismember engages the coils of the spring on and along which it isrotatable thereby varying the strength of the spring by a1- tering thelength of its operative part but withoutaltering its tension, while theother end of the spring bears on a second and separate and movablemember. This second member may be adjustable by itself for the purposeof varying the tension of the spring ina manner which will prevent thistension being altered when the coils. Conveniently the pitch of thescrewthread, I

which constitutes the connection between this member and thenonrotatable fixed part, is substantially the same as the pitch of thespring coils. The second member on which bears the other end of thespring engages a spindle which lies within the spring and can be movedby the weights to effect the engine control. This spindle and thedriving shaft for the weights are arranged substantially coaxial, butwith their adjacent ends spaced apart with a shaft-length interposedbetween these ends so that movement will be transmitted through thisshaft-length from the weights to the spindle and so to the one end ofthe spring. The weights and the spring are preferably enclosed within asubstantially cylindrical casing into the one end of which is screwedthe first member whose adjustment varies the efiective length or.strength of the spring. The spindle on which is the member en-' gagingthe other end of the spring is connected to a lever on a transverseshaft carried in bearings in a casing which surrounds the spring. Alever is fixed on one end or the other of this transverse shaft in amanner which permits the angular position of this lever about the shaftaxis to be altered as may be convenient when mounting the governor onthe engine. This lever serves to transmit the engine-controllingmovements from the governor weights.

With this improved construction it will be seen that it is possible tovary the strength of the spring by altering its efiective length withoutvarying the tension. Further by reason of the general construction ofthe casing and the arrangement of the means by which the movements aretransmitted from the governor to the engine control it is possible tomount the governor in such a position as may be suitable for making theconnections for the transmission of the controlling movements.

The invention may be carried into practice in various ways, but theaccompanying drawings illustrate by way of example a construction whichmay be employed. In these drawings:

Figure 1 is a side elevation of the improved governor.

Figure 2 is a view from the lefthand end as seen in Figure 1.

Figure 3 is a longitudinal sectional elevation the section being takenon the line 3-3 in Figure 2 looking in the direction of the arrows.

Figure 4 is a transverse section on the broken line 4-4 in Figure 3looking in the direction of the arrows,

Figure 5 is a transverse section on the line 5-5 in Figure 3.

Figure 6 is a side elevation of the modified form of lever shown at therighthand side of Figure 4, by which the control is eflected by thegovernor.

The driving shaft A of the governor is carried in bearings suitablyarranged in the one end of a cylindrical casing B. On the outer endportion of this shaft is fixed a pulley wheel A whose size is determinedin accordance with the desired speed ratio of th drive. The weights Care mounted on a collar C fixed on the inner end of the shaft A so thatas they swing outwards their lever arms C will tend to transmit movementin the direction of the axis of the shaft. Into the other end B of themain part of the cylindrical casing 13 fits an extension piece D whichcloses that end of the casing by what is in effect a partition D beyondwhich the extension projects with its exterior cylindrical and its endopen. In the centre of this partition D is an opening formed as asleeve-like guide D in which can freely slide a short length of shaftingE which lies coaxial with the driving shaft A and carries towards itsinner end a ball race E through which the arms of the weights C can acton that end of the shaft E and impart sliding movement thereto.

In the open end of the cylindrical extension D of the casing B is ascrewthread D of quick pitch and with this engages a correspondingthread F on the exterior of a short sleeve F having at its outer end anexternal flange F or other formation which will enable the sleeve to berotated in the extension of the casing. In a suitable position withinthis sleeve F is an inwardly projecting flange F of substantial width orthickness in the axial direction and the inner part of this flange isgrooved or formed as at F as a quick pitch screwthread, but the groovingis shaped to engage the coils of a spring G one extreme end G of whichis anchored by inserting it in a hole D in the partition D within thecasing DB. The engagement between the sleeve F and the spring coilsforms a connection between the one end of the effective part of thespring G and the fixed casing D which thus takes the spring reaction.Rotation of the sleeve F will move along the coils this connection withthe spring and thus alter its operative length, that is to say itsstrength or load.

The other, that is the outer end of the spring is formed into an eye Gwhich engages a thimble or collar H on the outer end portion of aspindle J which extends inwards towards the outer end of the slidingshaft length E in the partition D in the casing, the spindle J and thisshaft E being coaxial and their ends in effect abutting through a rollerK on the end of the spindle. This end of the spindle is pivotallyconnected at J to a short lever arm L on a transverselydisposed shaft Mcarried in bearings D in the extension D of the casing (see Figures 2and 4). By altering the position of the rotatable sleeve F which engagesthe coils of the spring G, the strength of the spring can be varied andthis can be done without affecting the tension. If desired the tensionas well as the strength of the sprin may be adjustable. The collar H isscrewed on the outer end part of the spindle J though other means may beprovided whereby this collar can be adjusted along the spindle. Thesetwo adjustments will not affect each other since they are at oppositeends of the spring. When the sleeve F has been adjusted it can be fixedby the set screw F Movements of the weights 0 as they swing out arecommunicated through the sliding shaftlength E, roller K and lever arm Lto the transverse shaft M against the action of the spring G. Thetransverse shaft M can be arranged in its bearings D so that its end onwhich a lever can be fixed will project for this purpose either from oneside or the other of the casing and the angular position in which thelever is fixed on the shaft may be as found convenient. This can be seenin Figure 2 where a lever N, also seen in Figure 1, is shown as fixed onthe one end of the shaft M which lies on the righthand side of Figure 2.On the lefthand side of that figure a lever N' is shown in chain linesin two difierent angular positions in which it may be placed on that endof the shaft M. Owing to the cylindrical exterior of the main part B ofthe casing the whole governor may be clamped in place in such an angularposition about its axis as may be convenient having regard to thedesirable position about that axis of the axis of the transverse shaft Mand the disposition of the control connections to the engine.

In a modified construction shown in Figures 4 and 6 the lever on thetransverse shaft M may be articulated, that is to say the main part N ofthis lever which is fixed on the end of the shaft may have pivotedthereto at N an extension N. The movement of the extension in relationto the main part N of the lever may be determined by a quadrant N on thelatter and over which the extension can swing between stops with aclamping nut N to fix it in the desired position. A spring N may beprovided about the pivot N of the extension lever N which will tend toswing this extension in a direction which will always return it to aposition against one of the stops. With this arrangement it is possibleto hold the engine throttle in the correct position for starting sincethe extension N of the lever can be freed and swing by hand into thestarting position and there clamped by the nut N After starting theextension can be released and moved by hand into its running positionand again clamped so that the governor may take over the control of theengine. If the spring N is provided this may automatically return thelever extension N to its runnin position. This latter arrangement may beemployed where there is a remote hand control and in that case the meansfor clamping the extension N to ,the main part N of the lever may bedispensed with.

With a governor constructed as described above the spring load lies onthe axis of the governor and thus causes the least friction on themoving parts. As for instance the transverse shaft M is arranged so thatit is not under load from the spring G.

When the weights C have swung out to their extreme positions the thrustrace E through which the movements are transmitted to the slidingshaft-length E will be in such a position that the face of this ballrace will come up against the end of the guide sleeve D in the partitionD within the casing. The lever N on the transverse shaft M whichactuates the engine control will then have been moved into the extremeposition into which it can be moved by the governor. This lever, ifformed with an extension N however, can be moved by hand or otherwisebeyond this position as for starting in the manner mentioned above.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a centrifugal governor for controlling the speed of an internalcombustion engine, the combination of a spindle with means'for drivingit, weights carried by this spindle so that they will be swung outwardsby centrifugal force as the spindle rotates, a. shaft member which iscoaxial with the driving spindle and is movable in the axial directionby the action of the gov-' ernor weights as they fly outwards, atransmission rod coaxial with the said sliding shaft member and servingas a connection between one end of that shaft and one end of a coiledspring which lies around this spindle, a member which on the one handengages the coils of this spring and on the other is in screwthreadedengagement with a fixed part and thus serves as an adjustable connectionbetween the spring and this fixed part, and means for transmitting tothe part controlled by the governor the movements imparted to the saidsliding shaft by the weights.

2. In a centrifugal governor for controlling the speed of an internalcombustion engine, the combination of a spindle with means for drivingit, weights carried by this spindle so that they will be swung outwardsby centrifugal force as the spindle rotates, a shaft member which iscoaxial with the driving spindle and is movable in the axial directionby the action of the governor weights as they fly outwards, atransmission rod coaxial with the said sliding shaft member and servingas a cmnection between one end of that shaft and one end of a coiledspring which lies around this spindle, a member which lies around thespring and between it and a fixed part in relation to which this memberis rotatable, the coils ofthe spring being engaged externally by thismember which is in screw-threaded engagement with the said fixed 'part,rotation of this member varying the claim 1 the combination with thetransmission rod, of means for adjusting the connection between the oneend of this rod and the end of the spring whereby the tension of thespring can be varied.

4. A centrifugal governor as claimed in claim 2 in which the screwthreadwhich constitutes the engagement between the fixed part and therotatable member has a pitch substantially the same as the pitch of thespring coils which are engaged by this rotatable member.

5. In a centrifugal governor as claimed in claim 1 the combination of acasing enclosing the coiled spring and having a partition through whichpasses and by which isguided the sliding shaft member, a transverseshaft carried in bearings in the casing and lying adjacent to thecooperating ends of the sliding shaft member and the transmission rod, alever on this transverse shaft connected to the adjacent end of thetransmission rod so that the lever will be moved as and when thetransmission rod is moved by the action of the governor weights, asecond lever on a part of this transverse shaft which lies outside thecasing, and means for transmitting the movements of this second lever tothe part controlled by the governor.

6. An adjustably mounted coiled spring for use with a centrifugalgovernor having a casing, weights and a spindle, comprising anadjustably mounted support on the spindle movable in the direction ofthe length of the spindle and supporting one end of the spring inadjusted position thereby to vary the tension of the spring,

and a sleeve threaded internally and externally,

the internal threads of which coact with the convolutions of the springwhile its external threads coact with the casing to change the relativepoint of connection of the sleeve with the spring, thereby to vary itsstrength.

ALICK DARBY DRAPER.

